Micropropagation of red raspberry and the influence of phloroglucinol

Micropropagation of 12 raspberry seedling selections and the cultivar ‘Malling Jewel’ has been achieved. A basic culture medium (Linsmaier and Skoog, 1965) supplemented with benzylaminopurine (BAP), 1.0 mg l^?1, and indol-3-yl butyric acid (IBA), 0.1 mg l^?1, was optimal for shoot proliferation. The presence of phloroglucinol (PG) at a concentration of 162 mg l^?1 significantly increased shoot number at all auxin: cytokinin concentrations. Removal of the cytokinin and increasing the concentration of IBA to 1.0 mg l^?1 resulted in adventitious root formation. PG synergistically promoted the number of roots per rooted culture but did not significantly increase the percentage rooting. Viable plants were produced from all genotypes when transplanted to soil.